The purposes of the proposed investigation are to further test and refine the Chronic Pain Experience Instrument (CPEI) and to refine the Chronic Pain Experience Model. A correlational, descriptive design using causal modeling methodology will be used for studying the complex experience of chronic pain. Specific aims include: verification of the defining characteristics of the chronic pain experience, verification of the reliability and validity of the CPEI, expansion of the substantive generalizability of the CPEI, refinement of the Chronic Pain Experience Model, description of the relationships between the chronic pain experience and other concepts in the Chronic Pain Experience Model, and comparison of the Chronic Pain Experience Models of the total sample and the sample groups related to each etiology. The purposive, nonrandom sample will include at least 300 subjects, with at least 100 representing each of 3 chronic pain groups: rheumatoid disease, functional headache, and chronic low back pain. The CPEI and 7 additional instruments will be used to test the concepts included in the Chronic Pain Experience Model. The significance of the study is in its attempt to increase understanding of chronic pain through the (1) identification and measurement of the characteristics of the chronic pain experience and (2) identification of the constructs which predict the response of persons to persistent pain. Focus on the person's unique, subjective pain response provides an approach to measurement which is consistent with nursing's focus. Development of an instrument which assesses the pain experience from the patient's perspective can lead to more individualized treatment and clearer identification of desired patient outcomes. Testing of the Model will provide valuable information regarding the predictors of how one responds to living with persistent pain.